Laser lift-off techniques are often used in the fabrication of various microelectronic devices, including flexible displays, flat panels, and semiconductor wafers. Laser lift-off typically involves removing or isolating one or more selected material layers by damaging, vaporizing, or otherwise altering an underlying sacrificial layer with high energy laser energy. For example, conventional laser lift-off can be performed with an excimer laser by generating an excimer (UV) laser line beam pulses having the requisite laser lift-off pulse parameters and scanning the line pulses across the target surface. However, even with the relatively superior performance with excimer-based products, capital cost and cost of ownership are onerous.
In order to make the laser lift-off process more accessible by reducing cost, techniques have been proposed where a solid state laser is used instead of an excimer laser. Some lower cost solid state laser-based laser lift-off system designs have attempted to utilize a smaller laser pulse spot instead of a laser pulse line. The solid state laser pulse spot is raster scanned to process the area or pattern where lift-off is to occur. Unfortunately, such attempts have not met with success. The lift-off targets are prone to “mura,” i.e., process non-uniformity, including moire patterns and other unevenness or non-uniformity that is generally unacceptable. Furthermore, processing (or “takt”) times tend to be larger than line based approaches. Consequently, the lower cost solid state laser approaches have been all but scrapped by industry. Thus, despite efforts to achieve a solid-state laser scanning laser lift-off system that is free of mura and poor takt times, there remains a need for systems and methods without these attendant drawbacks.
The foregoing and other objects, features, and advantages will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures which are not necessarily drawn to scale.